A. Technical Field
The present invention relates generally to networking systems, and more particularly to optical cross connect switching in optical networks.
B. Background of the Invention
As the result of continuous advances in technology, particularly in the area of networking such as the Internet, there is an increasing demand for communications bandwidth. For example, the transmission of data over a telephone company""s trunk lines, the transmission of images or video over the Internet, the transfer of large amounts of data as might be required in transaction processing, or videoconferencing implemented over a public telephone network typically require the high speed transmission of large amounts of data. As applications such as these become more prevalent, the demand for communications bandwidth capacity will only increase.
Optical fiber is a transmission medium that is well suited to meet this increasing demand. Optical fiber has an inherent bandwidth that is much greater than metal-based conductors, such as twisted pair or coaxial cable; and protocols such as the SONET optical carrier (OC) protocols have been developed for the transmission of data over optical fibers.
Optical fiber is used to form optical networks that carry data, voice and video over optical fibers using multiple wavelengths of light in parallel. Light is routed through the network from its originating location to its final destination. Since optical networks do not generally have a single continuous optical fiber path from every source to every destination, the light is switched as it travels through the optical network. Previously, this switching was accomplished using optical-electrical-optical (xe2x80x9cOEOxe2x80x9d) systems, where the light signal was converted to an electrical signal, switched electrically, then output optically.
However, because in OEO systems the signal must be converted from optical to electrical, switched, then converted back to optical, the OEO systems were relatively large, complex, and expensive. More seriously, the electrical systems have slower performance than optical systems. This means that use of an OEO system creates a bottleneck in the optical network, and an OEO system is undesirable.
Much effort is being expended on the development of an all-optical cross-connect switching system, using a variety of different technological approaches: movable mirrors, acousto-optic diffraction, electro-optic refraction, magneto-optic switching, movable bubbles, and liquid crystal addressable arrays to name a few. Each of these technologies has its own performance characteristics, advantages and disadvantages.
Also, at times an optical cross connect switch resides at nodes in a ring-mesh network and light signals received at the node may be of widely varying intensity. It is typically desirable to equalize the intensity of the signals before they are amplified or routed to another node.
Thus, what is needed is an optical cross connect switching system to switch optical signals in the optical domain, without converting the optical signals to electrical signals. The system preferably should also have the capability to equalize the intensity of the signals.
The present invention is an optical cross connect switching system. In one embodiment, a first optical fiber array carries optical destination signals and optical data signals. A switch configuration controller demultiplexes, converts optical signals to electrical signals and decodes the optical destinations for the optical data signals. A first mirror array controllably reflects the optical data signals from outputs of the first optical fiber-lens array. A second mirror array controllably reflects the optical data signals from the first mirror array. A second optical fiber-lens array receives the optical data signals reflected from the second mirror array. A position detector array detects the position of the optical data signals reflected from the second mirror array. A switch configuration controller uses the decoded optical destination signals and the detected position of the optical data signals to control the first and second mirror arrays to correctly direct the optical data signals from the first optical fiber array to the second optical fiber array.